title: Clinical and molecular characterization of colorectal cancer in young Moroccan patients.
abstract: OBJECTIVE
  Early-onset colorectal cancers are relatively rare. About 20% of colorectal cancers are familial or hereditary. Two autosomal dominantly inherited cancer syndromes are more studied: Lynch syndrome accounts for 2-5% of colorectal cancers and familial adenomatous polyposis represents 1% of total colorectal cancers. Unlike the familial adenomatous polyposis syndrome, there are no clinical features that help in easily recognizing Lynch syndrome. The young age of cancer occurrence could be a criterion that should raise a suspicion of Lynch syndrome. In Morocco, the average age at diagnosis of colorectal cancers according to the register of cancers of Casablanca is 56 years, which is 10 years earlier than in European countries. Our study aimed to assess the frequency and molecular characteristics of the Lynch syndrome in Moroccan early-onset colorectal cancers patients.
  
  
  METHODS
  The population analyzed included 70 patients. The criteria for inclusion of patients in this study were a colorectal cancers before age 50 and the exclusion of familial adenomatous polyposis. We started by searching for microsatellite instability, first by immunohistochemistry of 3 mismatch repair proteins (MLH1, MSH2 and MSH6) and with second confirmation using 4 monomorphic markers (BAT25, BAT26, NR21, and CAT25).
  
  
  RESULTS
  We found instability in 10/70 (15%) of the cases. The loss of expression affects more often the MLH1 protein, with 8 cases, versus 2 cases of altered MSH2. None of the 70 patients of the series fulfilled the Amsterdam II criteria, indicative of Lynch syndrome.
  
  
  CONCLUSIONS
  Further work needs to be done to discriminate hereditary cases from sporadic ones, but testing for microsatellite instability as a first step is important.
authors.affiliation: Medical School, Department of Genetic Laboratory, Casablanca, Morocco. a.benmoussa@yahoo.fr
authors.forename: Amal
authors.initials: A
authors.lastname: Benmoussa
authors.forename: Wafaa
authors.initials: W
authors.lastname: Badre
authors.forename: Monica
authors.initials: M
authors.lastname: Pedroni
authors.forename: Soumia
authors.initials: S
authors.lastname: Zamiati
authors.forename: Latifa
authors.initials: L
authors.lastname: Badre
authors.forename: Carmela
authors.initials: C
authors.lastname: Digregorio
authors.forename: Maurizio Ponz
authors.initials: MP
authors.lastname: De Leon
authors.forename: Selama
authors.initials: S
authors.lastname: Nadifi
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000235:genetics*; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000453:epidemiology / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D008875:Middle Aged; D009018:Morocco / Q000453:epidemiology; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D055815:Young Adult
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; C094443:G-T mismatch-binding protein; C501486:MLH1 protein, human; D009687:Nuclear Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein